/in/foo.cc: In constructor 'data::data(ll, ll, ll)':
/in/foo.cc:9:12: warning: 'data::len' will be initialized after [-Wreorder]
  ll sum,mi,len;
            ^~~
/in/foo.cc:9:5: warning:   'll data::sum' [-Wreorder]
  ll sum,mi,len;
     ^~~
/in/foo.cc:11:2: warning:   when initialized here [-Wreorder]
  data(ll L,ll S,ll M):len(L),sum(S),mi(M){}
  ^~~~